Roof rack crossbar



FIG. 1 is a perspective view of a roof rack crossbar showing my new design;

FIG. 2 is a front shallow perspective view thereof;

FIG. 3 is a side view thereof; and,

FIG. 4 is a plan elevation view thereof.

The break in the FIGS. 1, 3, and 4 drawings show indeterminate length. 

The ornamental design for a roof rack crossbar, as shown and described. 